JPH06123862A - Soft contact lens - Google Patents

Abstract

PURPOSE:To provide a soft contact lens ensuring good wearing feeling and having a high water content and high strength. CONSTITUTION:This soft contact lens consists of 2-50 pts.wt. diacrylic (methacrylic) ester represented by the formula, 20-90 pts.wt. vinyl-pyrrolidone-2- hydroxyethyl methacrylate and 8-50 pts.wt. monomer copolymerizable with them and has >=50% water content and high bending strength. In the formula, X is H or CH3 and (n) is an integer of 6-20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft contact lens. More specifically, the water content is 5
The present invention relates to a soft contact lens having a bending strength of 0% or more.

[0002]

2. Description of the Related Art It is needless to say that a contact lens is mainly intended to correct visual acuity, but since it is inserted into the inside of the eye, comfort is particularly required. From this point of view, it is generally said that the soft contact lens has a better wearing feeling to the human eye than the hard contact lens. The reason for this is that, in general, soft contact lenses are worn in a water-containing state, so that they do not give a strange feeling to the eyeball. In fact, it is said that a soft contact lens having a high water content has a better wearing feeling.
However, a soft contact lens having a high water content generally has low strength and is immersed in water for a long time, or conversely, dried, or when the lens is handled,
It was easy to cause cracks and deformation, and various problems were always caused by the low strength. From this point of view, the appearance of a soft contact lens having a high water content and high strength is desired.

[0003]

The problem to be solved is to find a method for obtaining a soft contact lens having a high water content with a good feeling of wearing and a high strength.

[0004]

In the present invention, as a solution to this problem, a monomer having water-soluble vinylpyrrolidone as a main raw material is a long-chain crosslinking agent having radical copolymerizability with this. An attempt to obtain a soft contact lens having a high water content and high strength by forming a water-containing cross-linked product of a difunctional (meth) acrylic ester represented by the following structural formula (1) Is.

The present invention will be described in detail below. As a raw material for soft contact lenses, conventionally, water-soluble 2-hydroxyethyl methacrylate, vinylpyrrolidone, acrylamide and the like have been obtained by copolymerization with a crosslinking agent. However, the cross-linking agent used here has few hydrophilic materials, and if the cross-linking agent is used in a large amount in order to increase the strength of the lens, the water content lowers at present. Some materials such as diacrylamide, which are extremely hydrophilic, are also known, but they are questioned for safety as contact lenses. As described above, at present, there is a contradiction between increasing the water content of the contact lens and the amount of the crosslinking agent used for increasing the strength. This is due to the fact that no good flexible long-chain crosslinkers have been found.

The present invention solves this problem by using a diacrylic (methacrylic) ester having a long-chain methylene unit represented by the following chemical formula 2 (Structural Formula 1) as a cross-linking agent, and has a good wearing feeling. The inventors have found a method of obtaining a soft contact lens having a high water content and high strength.

[0007]

[Chemical 2]

The monomer represented by the structural formula 1 has two acryl (methacryl) groups which are radically polymerizable functional groups and can be three-dimensionally crosslinked. Further, although the monomer represented by Structural Formula 1 has a methylene unit, it is a feature of the present invention that it does not have a strong hydrophobicity and surprisingly does not impair the water content.

The greatest feature of the present invention is that the diacrylic (methacrylic) ester represented by the structural formula 1 is used as a crosslinking agent, but the value of n in the structural formula 1 is extremely important. That is, the water content of the diacrylic (methacrylic) ester represented by Structural Formula 1 changes greatly depending on the value of n. In the present invention, the value of n in the structural formula 1 is usually an integer in the range of 6 to 20, though it depends on the desired water content. If the value of n is less than 6, the crosslinking effect will be too strong, the water content will decrease, and the material will become brittle, and it will be difficult to make a material having a water content of 50% or more as defined by the present invention and having strength. On the other hand, when it exceeds 20, the crosslinking effect becomes gradual, but the crosslinking effect becomes small, and the strength, especially the bending strength when containing water, becomes weak. From this meaning, in the present invention, the value of n in the structural formula 1 is usually in the range of 6 to 20. More preferably, the value of n is 7 to 1
An integer in the range 5 is used.

Next, in the contact lens of the present invention, vinylpyrrolidone or 2-hydroxyethyl methacrylate is used as a main component in addition to the diacrylic (methacryl) ester of structural formula 1. These compounds are useful monomers having excellent hydrophilicity and a diacrylic (methacrylic) ester represented by the structural formula 1 and having excellent radical polymerizability.

In the present invention, the diacryl (methacryl) ester of formula 1 and vinylpyrrolidone, or 2-hydroxyethylmethacrylate is 2 to 50 parts by weight of diacryl (methacryl) ester, and vinylpyrrolidone and 2-hydroxyethylmethacrylate. 20
~ 90 parts by weight are used as the main composition of contact lenses. When the amount of the diacrylic (methacrylic) ester is less than 2 parts by weight, the crosslinking effect is weak and a strong lens cannot be obtained. On the other hand, if it is used in excess of 50 parts by weight, crosslinking will proceed too much, and on the contrary, the lens will become brittle and the water content will not increase. If the amount of vinylpyrrolidone or 2-hydroxyethyl methacrylate is less than 20 parts by weight, it has no hydrophilicity and the water content does not increase. On the other hand, if the amount exceeds 90 parts by weight, the water content increases, but the crosslinking does not increase, so that a strong lens cannot be obtained. From this, in the present invention, the diacryl (methacryl) of structural formula 1 is
The ester and vinylpyrrolidone or 2-hydroxyethylmethacrylate are 2 to 50 parts by weight of a diacrylic (methacryl) ester, and vinylpyrrolidone,
20 to 90 parts by weight of 2-hydroxyethyl methacrylate is used as a good range.

Next, in the present invention, in addition to these diacryl (methacryl) ester of structural formula 1 and vinylpyrrolidone or 2-hydroxyethylmethacrylate, as long as the gist of the present invention is not impaired, these The polymerizable monomer can be used in the range of 8 to 50 parts by weight. The purpose is to add various characteristics to the contact lens and the manufacturing method thereof. For example, in addition to adjusting the bending strength to make the water content moderate, adjusting the polymerization rate, grinding contact lenses,
This is for improving workability such as polishing, facilitating curve design, and adjusting refractive index.

Specific examples of the monomers used for these purposes are methyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate,
2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, ethylene glycol diacrylate (methacrylate), propylene glycol diacrylate (methacrylate), neopentyl glycol diacrylate (methacrylate), diethylene glycol diacrylate (methacrylate), Triethylene glycol diacrylate (methacrylate), tetraethylene glycol diacrylate (methacrylate), bisphenol A diacrylate (methacrylate),
2,2bis (4-acryloxyethoxyphenyl) propane, 2,2bis (4-acryloxydiethoxyphenyl) propane, 2,2bis (4-acryloxytriethoxyphenyl) propane, 2,2bis (4 -Acryloxytetraethoxyphenyl) propane, 2,2 bis (4
-Methacryloxyethoxyphenyl) propane, 2,2
Bis (4-methacryloxydiethoxyphenyl) propane, 2,2bis (4-methacryloxytriethoxyphenyl) propane, glycerin triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, etc. Acrylate (methacrylate) can be mentioned.
Furthermore, styrene, α-methyl styrene, chlorostyrene,
A monomer having a vinyl group such as divinylbenzene can also be effectively used. These are just examples and the present invention is not limited thereto.

Next, these diacrylic (methacrylic) ester of structural formula 1 and vinylpyrrolidone, or 2
-Hydroxyethyl methacrylate and a monomer copolymerizable therewith are mixed and copolymerized. At this time, a polymerization initiator is used, but in the present invention, there is no particular limitation,
A usual radical polymerization initiator can be used.

The monomer mixture added with an appropriate amount of radical polymerization initiator is poured into a polymerization mold made of metal, glass, plastic or the like having a designed curvature, heat-cured, and co-polymerized. A combined resin or lens is obtained. The heat curing temperature is 30 to 10 in the present invention.
Although about 0 ° C. is adopted, it may be changed depending on the purpose. Further, in the present invention, it is needless to say that various additives such as an ultraviolet absorber can be added to the monomer according to the purpose, and it is more effective. The copolymer resin obtained in the present invention can be used as a contact lens by being hydrated as it is. However, in many cases, after this, a conventional means is used for the contact lens intended for the copolymer resin. Then, the soft contact lens can be obtained by performing grinding and polishing. Hereinafter, the present invention will be described with reference to examples.

Example (1) 1,9 nonanediol dimethacrylate 5 parts by weight represented by the following chemical formula 3 (structural formula 2) N-vinylpyrrolidone 70 parts by weight methyl methacrylate 20 parts by weight 2-hydroxyethyl methacrylate 5 parts by weight The mixture was mixed well to obtain a monomer solution. To this, 0.7 part by weight of azobisisobutyronitrile was added as a polymerization initiator, and the mixture was placed in a glass tube and heated under nitrogen at 42 ° C. for 5 hours.
Polymerization was performed at 60 ° C. for 15 hours and at 85 ° C. for 2 hours to obtain a colorless and transparent copolymer. This copolymer was ground and polished to prepare a test piece (about 12 mmφ × 0.8 mm). Moisture content A test piece is put in a vacuum drier and placed under reduced pressure at 25 ° C. for 24 hours, and the dry weight after that is determined and defined as Dw. Next, the dried test piece was immersed in physiological saline at 80 ° C. for 24 hours and allowed to swell, then, this was cooled as it was, the physiological saline was kept constant at 37 ° C., and the weight after reaching parallel swelling was determined. Let this be Ww. Bending test The above sample, which has reached parallel swelling, is bent 180 degrees and folded in two. Next, fold it in the opposite direction in the same way and make a two-fold fold. This operation counts as one bend. This operation is repeated. Judgment No change occurs after 30 times ◎ 20 times or more partial cracks ○ 10 times or more cracks △ Less than 10 times crack × Results of Example (1) Moisture content 52.4% Bending Test ◎

[0017]

[Chemical 3]

Comparative Example (1) Instead of the dimethacrylic ester represented by the structural formula 2 in Example (1), 5 parts by weight of propylene glycol dimethacrylate represented by the following chemical formula 4 (structural formula 3) was used. Other than that, polymerization was carried out under exactly the same conditions as in Example (1) to produce the same test piece as in Example (1), and the water content and bending test were conducted. Results of Comparative Example (1) Moisture content 43.6% Bending test △

[0019]

[Chemical 4]

Example (2) 1,10 decanediol diacrylate represented by the following chemical formula 5 (structural formula 4) 10 parts by weight N-vinylpyrrolidone 65 parts by weight Methyl methacrylate 20 parts by weight 2-hydroxyethyl methacrylate 5 parts by weight The mixture was mixed well to obtain a monomer solution. To this, 0.7 part by weight of azobisisobutyronitrile was added as a polymerization initiator, and the mixture was placed in a glass tube and heated under nitrogen at 42 ° C. for 5 hours.
Polymerization was performed at 60 ° C. for 15 hours and at 85 ° C. for 2 hours to obtain a colorless and transparent copolymer. The same test piece as in Example (1) was prepared, and the water content and bending test were performed. Results of Example (2) Moisture content 56.1% Bending test ◎

[0021]

[Chemical 5]

Example (3) 1,9 Nonanediol dimethacrylate represented by the above structural formula 3 3 parts by weight N-vinylpyrrolidone 68 parts by weight Methyl methacrylate 20 parts by weight 2-hydroxyethyl methacrylate 5 parts by weight Stearyl methacrylate 4 parts by weight Other than that, polymerization was carried out under exactly the same conditions as in Example (1) to produce the same test piece as in Example (1), and the water content and bending test were conducted. Results of Example (3) Moisture content 69.3% Bending test ◎

Example (4) 1,7 heptanediol dimethacrylate represented by the following chemical formula 6 (structural formula 5) 5 parts by weight N-vinylpyrrolidone 65 parts by weight Methyl methacrylate 20 parts by weight 2-hydroxyethyl methacrylate 5 parts by weight 2 -Ethylhexyl methacrylate 5 parts by weight Polymerization was carried out under the same conditions as in Example (1) except that the same test piece as in Example (1) was prepared, and the water content and bending test were conducted. Results of Example (4) Moisture content 61.7% Bending test ◎

[0024]

[Chemical 6]

Claims (1)

[Claims] 1. 2 to 50 parts by weight of a diacrylic (methacrylic) ester represented by the following chemical formula 1 (structural formula 1) and vinylpyrrolidone and 2-hydroxyethyl methacrylate 2
0 to 90 parts by weight and monomers 8 to 5 copolymerizable therewith
A soft contact lens consisting of 0 parts by weight and having a high bending strength with a water content of 50% or more. [Chemical 1]